第12节第二种shellcode编写实战(1)

一、C语言方式编写shellcode

1. 新建0.createshellcode.cpp文件：用于生成整个项目的shellcode文件，便于其他项目加载执行shellcode。

#include "a.start.h"
#include "z.end.h"
#include "shellcode.h"

#pragma optimize("", off ) 
#pragma comment(linker,"/entry:EntryMain")

int EntryMain()
{
    // 获取shellcode片段大小
    DWORD dwShellcodeSize = (DWORD)ShellCodeEnd - (DWORD)ShellCodeStart;

    DWORD   dwWriten = 0;
    HANDLE  hFile = NULL;

    // 创建文件，用于保存最后的shellcode
    hFile = CreateFileA("shellcode.bin", GENERIC_WRITE | GENERIC_READ, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);
    if (hFile == INVALID_HANDLE_VALUE)
    {
        return -1;
    }

    // 将shellcode写入到文件
    if (WriteFile(hFile, ShellCodeStart, dwShellcodeSize, &dwWriten, NULL) == FALSE)
    {
        CloseHandle(hFile);
        return -1;
    }

    CloseHandle(hFile);

    return 0;
}

2. 新建a.start.h、z.end.h，以及对应的a.start.cpp、z.end.cpp，分别用于标记shellcode的开始和结束。

a.start.h：

#pragma once

// 用于标记shellcode开始
void ShellCodeStart();

a.start.cpp：

#include "a.start.h"
#include "shellcode.h"

// 用于标记shellcode开始
void ShellCodeStart()
{
    // shellcode执行的主要功能
    ShellcodeMain();
}

z.end.h：

#pragma once

// 用于标记shellcode结束
void ShellCodeEnd();

z.end.cpp：

// 次函数仅用来标记shellcode结尾
void ShellCodeEnd()
{

}

3. 新建shellcode.h，以及对应的shellcode.cpp，用于编写shellcode执行的主要功能代码。

shellcode.h：

#pragma once

#include <windows.h>
#include <Winternl.h>

HMODULE GetKernel32BaseAddress();
FARPROC _GetPorcAddress();

int ShellcodeMain();

// 创建文件
int DoCreateFile();
// 弹框提示
int DoMessageBox();

shellcode.cpp：

#include "shellcode.h"

// shellcode主要执行的功能
int ShellcodeMain()
{
    // 创建文件
    DoCreateFile();

    // 弹框提示
    DoMessageBox();

    // 其他功能...

    return 0;
}

// 功能：创建文件 D:\1.txt
int DoCreateFile()
{
    // 获取GetPorcAddress函数地址
    typedef FARPROC(WINAPI* FN_GetProcAddress)(__in HMODULE hModule, __in LPCSTR lpProcName);
    FN_GetProcAddress fn_GetProcAddress = (FN_GetProcAddress)_GetPorcAddress();
    if (fn_GetProcAddress)
    {
        // 获取LoadLibraryA函数地址
        char szLoadLibraryA[] = { 'L','o','a','d','L','i','b','r','a','r','y','A',0 };
        typedef HMODULE(WINAPI* FN_LoadLibraryA)(__in LPCSTR lpLibFileName);
        FN_LoadLibraryA fn_LoadLibraryA = (FN_LoadLibraryA)fn_GetProcAddress(GetKernel32BaseAddress(), szLoadLibraryA);
        if (fn_LoadLibraryA)
        {
            // 获取CreateFileA函数地址
            char szCreateFileA[] = { 'C','r','e','a','t','e','F','i','l','e','A',0 };
            typedef HANDLE(WINAPI* FN_CreateFileA)(
                _In_ LPCSTR lpFileName,
                _In_ DWORD dwDesiredAccess,
                _In_ DWORD dwShareMode,
                _In_opt_ LPSECURITY_ATTRIBUTES lpSecurityAttributes,
                _In_ DWORD dwCreationDisposition,
                _In_ DWORD dwFlagsAndAttributes,
                _In_opt_ HANDLE hTemplateFile
                );
            FN_CreateFileA fn_CreateFileA = (FN_CreateFileA)fn_GetProcAddress(GetKernel32BaseAddress(), szCreateFileA);
            // 执行CreateFileA
            char szFilePath[] = { 'D',':','\\','1','.','t','x','t',0 };
            fn_CreateFileA(szFilePath, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, 0, NULL);
        }
    }

    return 0;
}

// 功能：弹框提示
int DoMessageBox()
{
    // 获取GetPorcAddress函数地址
    typedef FARPROC(WINAPI* FN_GetProcAddress)(__in HMODULE hModule, __in LPCSTR lpProcName);
    FN_GetProcAddress fn_GetProcAddress = (FN_GetProcAddress)_GetPorcAddress();
    if (fn_GetProcAddress)
    {
        // 获取LoadLibraryA函数地址
        char szLoadLibraryA[] = { 'L','o','a','d','L','i','b','r','a','r','y','A',0 };
        typedef HMODULE(WINAPI* FN_LoadLibraryA)(__in LPCSTR lpLibFileName);
        FN_LoadLibraryA fn_LoadLibraryA = (FN_LoadLibraryA)fn_GetProcAddress(GetKernel32BaseAddress(), szLoadLibraryA);
        if (fn_LoadLibraryA)
        {
            // 获取MessageBoxA函数地址
            char szUser32[] = { 'U','s','e','r','3','2','.','d','l','l',0 };
            char szMessageBoxA[] = { 'M','e','s','s','a','g','e','B','o','x','A',0 };
            typedef int (WINAPI* FN_MessageBoxA)(__in_opt HWND hWnd, __in_opt LPCSTR lpText, __in_opt LPCSTR lpCaption, __in UINT uType);
            FN_MessageBoxA fn_MessageBoxA = (FN_MessageBoxA)fn_GetProcAddress(fn_LoadLibraryA(szUser32), szMessageBoxA);
            // 执行MessageBoxA
            char szCaption[] = { 't','i','t','l','e',0 };
            char szText[] = { 'H','e','l','l','o',' ','W','o','r','l','d', 0 };
            fn_MessageBoxA(0, szText, szCaption, MB_OK | MB_ICONINFORMATION);
        }
    }

    return 0;
}

// 获取kernel32基址
HMODULE GetKernel32BaseAddress()
{
    HMODULE hKernel32 = NULL;

    // 用户保存模块名
    WCHAR wszModuleName[MAX_PATH];

#ifdef _WIN64    // 64位PEB偏移为0x60
    PPEB lpPeb = (PPEB)__readgsqword(0x60);
#else            // 32位PEB偏移为0x30
    PPEB lpPeb = (PPEB)__readfsdword(0x30);
#endif

    PLIST_ENTRY pListHead = &lpPeb->Ldr->InMemoryOrderModuleList;
    PLIST_ENTRY pListData = pListHead->Flink;

    // 遍历所有模块
    while (pListData != pListHead)
    {
        PLDR_DATA_TABLE_ENTRY pLDRData = CONTAINING_RECORD(pListData, LDR_DATA_TABLE_ENTRY, InMemoryOrderLinks);

        DWORD dwLen = pLDRData->FullDllName.Length / 2;
        if (dwLen > 12)    // 12 是"kernel32.dll"的长度，获取到的完整路径肯定要比模块名长
        {
            // 从获取到的模块完整路径中提取模块名
            for (size_t i = 0; i < 12; i++)
            {
                wszModuleName[11 - i] = pLDRData->FullDllName.Buffer[dwLen - 1 - i];
            }

            // 最终要获取的目标模块名（"kernel32.dll"），逐个字节比较，包含大小写。
            if ((wszModuleName[0] == 'k' || wszModuleName[0] == 'K') &&
                (wszModuleName[1] == 'e' || wszModuleName[1] == 'E') &&
                (wszModuleName[2] == 'r' || wszModuleName[2] == 'R') &&
                (wszModuleName[3] == 'n' || wszModuleName[3] == 'N') &&
                (wszModuleName[4] == 'e' || wszModuleName[4] == 'E') &&
                (wszModuleName[5] == 'l' || wszModuleName[5] == 'L') &&
                (wszModuleName[6] == '3') &&
                (wszModuleName[7] == '2') &&
                (wszModuleName[8] == '.') &&
                (wszModuleName[9] == 'd' || wszModuleName[9] == 'D') &&
                (wszModuleName[10] == 'l' || wszModuleName[10] == 'L') &&
                (wszModuleName[11] == 'l' || wszModuleName[11] == 'L'))
            {
                hKernel32 = (HMODULE)pLDRData->DllBase;
                break;
            }
        }
        pListData = pListData->Flink;
    }
    return hKernel32;
}

// 获取GetPorcAddress函数地址
FARPROC _GetPorcAddress()
{
    // 保存最终结果
    FARPROC pGetPorcAddress = NULL;

    // kernel32基址
    HMODULE hKernel32 = GetKernel32BaseAddress();
    if (!hKernel32)
    {
        return NULL;
    }

    PIMAGE_DOS_HEADER lpDosHeader = (PIMAGE_DOS_HEADER)hKernel32;
    PIMAGE_NT_HEADERS lpNTHeader = (PIMAGE_NT_HEADERS)((unsigned char*)hKernel32 + lpDosHeader->e_lfanew);

    // 模块有效性验证
    if (!lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].Size)
    {
        return NULL;
    }
    if (!lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress)
    {
        return NULL;
    }

    // 通过导出表中的导出函数名，定位"GetProcAddress"的位置
    PIMAGE_EXPORT_DIRECTORY lpExports = (PIMAGE_EXPORT_DIRECTORY)((unsigned char*)hKernel32 + lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress);
    PDWORD lpdwFunName = (PDWORD)((unsigned char*)hKernel32 + lpExports->AddressOfNames);
    PWORD lpdwOrd = (PWORD)((unsigned char*)hKernel32 + lpExports->AddressOfNameOrdinals);
    PDWORD lpdwFunAddr = (PDWORD)((unsigned char*)hKernel32 + lpExports->AddressOfFunctions);

    for (DWORD dwLoop = 0; dwLoop <= lpExports->NumberOfNames - 1; dwLoop++)
    {
        char* pFunName = (char*)(lpdwFunName[dwLoop] + (unsigned char*)hKernel32);
        // 比较函数名
        if (
            pFunName[0] == 'G' &&
            pFunName[1] == 'e' &&
            pFunName[2] == 't' &&
            pFunName[3] == 'P' &&
            pFunName[4] == 'r' &&
            pFunName[5] == 'o' &&
            pFunName[6] == 'c' &&
            pFunName[7] == 'A' &&
            pFunName[8] == 'd' &&
            pFunName[9] == 'd' &&
            pFunName[10] == 'r' &&
            pFunName[11] == 'e' &&
            pFunName[12] == 's' &&
            pFunName[13] == 's'
            )
        {
            pGetPorcAddress = (FARPROC)(lpdwFunAddr[lpdwOrd[dwLoop]] + (unsigned char*)hKernel32);
            break;
        }
    }
    return pGetPorcAddress;
}

最后的框架结构如下图：

第12节第二种shellcode编写实战(1)-LMLPHP

后续开发所有功能都可以在遵循shellcode编写原则的基础上，以新的.h头文件.cpp源文件进行扩展。

二、C++类方式编写shellcode

也可以使用C++类的方式进行编写，比如将shellcode.cpp改为CDoShellcode类的方式实现：

shellcode.h：

#pragma once

#include <windows.h>
#include <Winternl.h>

class CDoShellcode
{
private:
     HMODULE GetKernel32BaseAddress();
     FARPROC _GetPorcAddress();

public:
     // 创建文件
     int DoCreateFile();
     // 弹框提示
     int DoMessageBox();
};

shellcode.cpp：

#include "shellcode.h"

// 功能：创建文件 D:\1.txt
int CDoShellcode::DoCreateFile()
{
    // 获取GetPorcAddress函数地址
    typedef FARPROC(WINAPI* FN_GetProcAddress)(__in HMODULE hModule, __in LPCSTR lpProcName);
    FN_GetProcAddress fn_GetProcAddress = (FN_GetProcAddress)_GetPorcAddress();
    if (fn_GetProcAddress)
    {
        // 获取LoadLibraryA函数地址
        char szLoadLibraryA[] = { 'L','o','a','d','L','i','b','r','a','r','y','A',0 };
        typedef HMODULE(WINAPI* FN_LoadLibraryA)(__in LPCSTR lpLibFileName);
        FN_LoadLibraryA fn_LoadLibraryA = (FN_LoadLibraryA)fn_GetProcAddress(GetKernel32BaseAddress(), szLoadLibraryA);
        if (fn_LoadLibraryA)
        {
            // 获取CreateFileA函数地址
            char szCreateFileA[] = { 'C','r','e','a','t','e','F','i','l','e','A',0 };
            typedef HANDLE(WINAPI* FN_CreateFileA)(
                _In_ LPCSTR lpFileName,
                _In_ DWORD dwDesiredAccess,
                _In_ DWORD dwShareMode,
                _In_opt_ LPSECURITY_ATTRIBUTES lpSecurityAttributes,
                _In_ DWORD dwCreationDisposition,
                _In_ DWORD dwFlagsAndAttributes,
                _In_opt_ HANDLE hTemplateFile
                );
            FN_CreateFileA fn_CreateFileA = (FN_CreateFileA)fn_GetProcAddress(GetKernel32BaseAddress(), szCreateFileA);
            // 执行CreateFileA
            char szFilePath[] = { 'D',':','\\','1','.','t','x','t',0 };
            fn_CreateFileA(szFilePath, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, 0, NULL);
        }
    }

    return 0;
}

// 功能：弹框提示
int CDoShellcode::DoMessageBox()
{
    // 获取GetPorcAddress函数地址
    typedef FARPROC(WINAPI* FN_GetProcAddress)(__in HMODULE hModule, __in LPCSTR lpProcName);
    FN_GetProcAddress fn_GetProcAddress = (FN_GetProcAddress)_GetPorcAddress();
    if (fn_GetProcAddress)
    {
        // 获取LoadLibraryA函数地址
        char szLoadLibraryA[] = { 'L','o','a','d','L','i','b','r','a','r','y','A',0 };
        typedef HMODULE(WINAPI* FN_LoadLibraryA)(__in LPCSTR lpLibFileName);
        FN_LoadLibraryA fn_LoadLibraryA = (FN_LoadLibraryA)fn_GetProcAddress(GetKernel32BaseAddress(), szLoadLibraryA);
        if (fn_LoadLibraryA)
        {
            // 获取MessageBoxA函数地址
            char szUser32[] = { 'U','s','e','r','3','2','.','d','l','l',0 };
            char szMessageBoxA[] = { 'M','e','s','s','a','g','e','B','o','x','A',0 };
            typedef int (WINAPI* FN_MessageBoxA)(__in_opt HWND hWnd, __in_opt LPCSTR lpText, __in_opt LPCSTR lpCaption, __in UINT uType);
            FN_MessageBoxA fn_MessageBoxA = (FN_MessageBoxA)fn_GetProcAddress(fn_LoadLibraryA(szUser32), szMessageBoxA);
            // 执行MessageBoxA
            char szCaption[] = { 't','i','t','l','e',0 };
            char szText[] = { 'H','e','l','l','o',' ','W','o','r','l','d', 0 };
            fn_MessageBoxA(0, szText, szCaption, MB_OK | MB_ICONINFORMATION);
        }
    }

    return 0;
}

// 获取kernel32基址
HMODULE CDoShellcode::GetKernel32BaseAddress()
{
    HMODULE hKernel32 = NULL;

    // 用户保存模块名
    WCHAR wszModuleName[MAX_PATH];

#ifdef _WIN64    // 64位PEB偏移为0x60
    PPEB lpPeb = (PPEB)__readgsqword(0x60);
#else            // 32位PEB偏移为0x30
    PPEB lpPeb = (PPEB)__readfsdword(0x30);
#endif

    PLIST_ENTRY pListHead = &lpPeb->Ldr->InMemoryOrderModuleList;
    PLIST_ENTRY pListData = pListHead->Flink;

    // 遍历所有模块
    while (pListData != pListHead)
    {
        PLDR_DATA_TABLE_ENTRY pLDRData = CONTAINING_RECORD(pListData, LDR_DATA_TABLE_ENTRY, InMemoryOrderLinks);

        DWORD dwLen = pLDRData->FullDllName.Length / 2;
        if (dwLen > 12)    // 12 是"kernel32.dll"的长度，获取到的完整路径肯定要比模块名长
        {
            // 从获取到的模块完整路径中提取模块名
            for (size_t i = 0; i < 12; i++)
            {
                wszModuleName[11 - i] = pLDRData->FullDllName.Buffer[dwLen - 1 - i];
            }

            // 最终要获取的目标模块名（"kernel32.dll"），逐个字节比较，包含大小写。
            if ((wszModuleName[0] == 'k' || wszModuleName[0] == 'K') &&
                (wszModuleName[1] == 'e' || wszModuleName[1] == 'E') &&
                (wszModuleName[2] == 'r' || wszModuleName[2] == 'R') &&
                (wszModuleName[3] == 'n' || wszModuleName[3] == 'N') &&
                (wszModuleName[4] == 'e' || wszModuleName[4] == 'E') &&
                (wszModuleName[5] == 'l' || wszModuleName[5] == 'L') &&
                (wszModuleName[6] == '3') &&
                (wszModuleName[7] == '2') &&
                (wszModuleName[8] == '.') &&
                (wszModuleName[9] == 'd' || wszModuleName[9] == 'D') &&
                (wszModuleName[10] == 'l' || wszModuleName[10] == 'L') &&
                (wszModuleName[11] == 'l' || wszModuleName[11] == 'L'))
            {
                hKernel32 = (HMODULE)pLDRData->DllBase;
                break;
            }
        }
        pListData = pListData->Flink;
    }
    return hKernel32;
}

// 获取GetPorcAddress函数地址
FARPROC CDoShellcode::_GetPorcAddress()
{
    // 保存最终结果
    FARPROC pGetPorcAddress = NULL;

    // kernel32基址
    HMODULE hKernel32 = GetKernel32BaseAddress();
    if (!hKernel32)
    {
        return NULL;
    }

    PIMAGE_DOS_HEADER lpDosHeader = (PIMAGE_DOS_HEADER)hKernel32;
    PIMAGE_NT_HEADERS lpNTHeader = (PIMAGE_NT_HEADERS)((unsigned char*)hKernel32 + lpDosHeader->e_lfanew);

    // 模块有效性验证
    if (!lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].Size)
    {
        return NULL;
    }
    if (!lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress)
    {
        return NULL;
    }

    // 通过导出表中的导出函数名，定位"GetProcAddress"的位置
    PIMAGE_EXPORT_DIRECTORY lpExports = (PIMAGE_EXPORT_DIRECTORY)((unsigned char*)hKernel32 + lpNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress);
    PDWORD lpdwFunName = (PDWORD)((unsigned char*)hKernel32 + lpExports->AddressOfNames);
    PWORD lpdwOrd = (PWORD)((unsigned char*)hKernel32 + lpExports->AddressOfNameOrdinals);
    PDWORD lpdwFunAddr = (PDWORD)((unsigned char*)hKernel32 + lpExports->AddressOfFunctions);

    for (DWORD dwLoop = 0; dwLoop <= lpExports->NumberOfNames - 1; dwLoop++)
    {
        char* pFunName = (char*)(lpdwFunName[dwLoop] + (unsigned char*)hKernel32);
        // 比较函数名
        if (
            pFunName[0] == 'G' &&
            pFunName[1] == 'e' &&
            pFunName[2] == 't' &&
            pFunName[3] == 'P' &&
            pFunName[4] == 'r' &&
            pFunName[5] == 'o' &&
            pFunName[6] == 'c' &&
            pFunName[7] == 'A' &&
            pFunName[8] == 'd' &&
            pFunName[9] == 'd' &&
            pFunName[10] == 'r' &&
            pFunName[11] == 'e' &&
            pFunName[12] == 's' &&
            pFunName[13] == 's'
            )
        {
            pGetPorcAddress = (FARPROC)(lpdwFunAddr[lpdwOrd[dwLoop]] + (unsigned char*)hKernel32);
            break;
        }
    }
    return pGetPorcAddress;
}

然后将a.start.cpp中的ShellCodeStart函数改为：

void ShellCodeStart()
{
    CDoShellcode shellcode;

    // 创建文件
    shellcode.DoCreateFile();

    // 弹框提示
    shellcode.DoMessageBox();

    // 其他功能...
}

这样即可实现类的方式执行shellcode功能。

测试：运行以上代码对应生成的exe文件，会在当前路径下生成shellcode.bin文件，该文件就是我们最后得到的shellcode文件。使用编写shellcode加载器加载执行shellcode.bin测试效果。

如果有任何问题，可以在我们的知识社群中提问和沟通交流：

第12节第二种shellcode编写实战(1)-LMLPHP

一个人走得再快，不如一群人走得更远！🤜🤛

imbyter代码酷